Germany's reunification plunge
Many call it a miracle, Germany's peaceful revolution in 1989 and reunification less than a year later, which is being remembered this weekend.
But Matthias Platzeck caused an uproar when he compared reunification to the Anschluss, Hitler's annexation of Austria in 1939.
Mr Platzeck does not want East Germany back, far from it. He was among the organisers of the popular protests that brought down the Berlin Wall.
Since 2002, this popular Social Democrat politician has been the prime minister of Brandenburg, Germany's most economically dynamic state.
But in the rush towards reunification, he believes many mistakes were made.
'Still in the East'
The rule, he said, was "what's good comes from the West, what's bad comes from the East".
"Polls suggest that 50% of people here haven't really arrived in the West in their heads and in their hearts," he said.
"Because 80% of East Germans have had to learn a new job, every second family has experienced unemployment. So it's not like everything is worth celebrating."
Speaking to a group of foreign journalists, Mr Platzeck said he had seldom received so many e-mails as in the last few weeks, supportive from the East and critical from the West.
"I think it shows what's going on in the country," he added.
"Westerners wrote 'We've spent so much money on you - be grateful'."
By most standards, the EU's biggest nation is a success story, an economic powerhouse with much to be proud of - high export rates, low unemployment and growing political self-confidence.
Living standards in the former East Germany have improved thanks to huge transfers from the West - an estimated $1.8tn (£1.14tn; 1.3tn euros).
But according to the Ifo economic research institute, the income of the average east German household is only 53% that of its Western equivalent.
So where has all the money gone?
Cold War, Tropical peace
Much of it has been spent on welfare benefits. Unemployment in the East stands at 11.5%, twice as high as in west Germany.
Autobahns and telephone networks have been upgraded, historic cities like Dresden and Leipzig restored to their former glory, new leisure facilities built.
The most unusual of the latter stands in a field an hour's drive from Berlin, and it encapsulates some of the successes and failures of reunification.
It is a grey cold day, but step inside and the temperature is a constant C26.
The chirping of exotic birds grows louder as you walk past a Buddha statue into a palm-tree grove.
This is Tropical Islands. It is said to be the largest indoor waterpark in the world, housed in the world's largest free-standing dome - actually a disused hangar where the Statue of Liberty could stand upright.
Twenty years ago, the then Chancellor Helmut Kohl promised East Germans they would see blooming landscapes.
I asked company spokesman Patrick Kastner if he had had in mind something like Tropical Islands.
"We have lots of nice plants here and that's a picture for what may happen in East Germany," he laughed.
"But in fact we have 500 employees from all over the region. We make holidays and not war."
On the site of the resort there used to be a military base.
"Up to 2,000 Russian soldiers and nuclear weapons were stationed here," Mr Kastner explained. "It was top secret."
It no longer is. Last year, 900,000 visitors came to Tropical Islands, developed by a Malaysian company with the help of $23m in subsidies.
One big plunge
But there are also drawbacks, as Ole Bested Hensing, the CEO of Tropical Islands, told me.
"We're really losing population, especially in Brandenburg," he said.
"Today we only have 50% of the schoolchildren we had 10 years ago."
When the company wanted to open a kindergarten for the employees, Mr Hensing said, local politicians were very angry.
"They said, if you open your own kindergarten, then we have to close the public kindergartens," he recalled.
With more than two million people leaving East Germany in the last 20 years, companies also face serious difficulties in recruiting staff.
At Tropical Islands, Mr Hensing explained "many of our employees have travel distances of up to 140km one way. In the very near region there are just not enough people."
To supplement wages of around 1,300 euros, the company offers petrol vouchers to employees who run out of money by the end of the month.
The visitors look happy in their swimsuits and flip-flops but not all feel they have something to celebrate on Sunday.
"We're not really united," said Kai Dietrich from Berlin.
"It's still East and West - in the wages, the politics, in our heads. Unfortunately, not much has changed, except that the Wall is gone."
Michael Beist, from Munich, is more positive: "I think that in the East they've been using our money well, because it's bringing both countries together. You can see the progress. It made no sense for us to be forever separated."
Before I leave Tropical Islands, I wait my turn on the highest water slide tower in Germany.
It is as high as a nine-floor building, scary but exhilarating. Just like this whole country must have felt 20 years ago, when it took one big plunge into the unknown.